Pseudabdounia recticona (Winkler, 1874) Ebersole & Cicimurri & Stringer, 2019

Ebersole, Jun A., Cicimurri, David J. & Stringer, Gary L., 2019, Taxonomy and biostratigraphy of the elasmobranchs and bony fishes (Chondrichthyes and Osteichthyes) of the lower-to-middle Eocene (Ypresian to Bartonian) Claiborne Group in Alabama, USA, including an analysis of otoliths, European Journal of Taxonomy 585, pp. 1-274 : 90-91

Pseudabdounia recticona (Winkler, 1874) gen. et comb. nov.

Fig. 32 S–JJ

Galeocerdo recticonus Winkler, 1874a: 26 .

Galeus recticonus – Leriche 1905: 135 , pl. 8, figs 44–53.

Eugaleus recticonus – Casier 1950: 18 , pl. 2, fig. 9.

Galeorhinus recticonus – Von der Hocht 1979: 40 .

Abdounia recticonus – Cappetta 1980a: 37 .

Abdounia recticona – Ward & Wiest 1990: 84 .

Material examined

UNITED STATES OF AMERICA – Alabama • 168 isolated teeth; Claiborne Group ; ANSP 23414 , GSA-V694, GSA-V703, MMNS VP-8213 (2 specimens), MSC 34405.4 , MSC 35767.1 – 5 , MSC 37115.1 – 3 , MSC 37138, MSC 37155, MSC 37160, MSC 37167.1 – 4 , MSC 37193, MSC 37318.1 , MSC 37318.3 , MSC 37629.1 – 5 , MSC 37634.1 – 22 , MSC 37635.1 , MSC 37647, MSC 37665.1 – 3 , MSC 37679.1 – 2 , MSC 37680.1 – 3 , MSC 38286, MSC 38287.1 – 2 , MSC 38831, MSC 38970, NJSM 24025 (3 specimens), SC 2012.47.164 (28 specimens), SC 2012.47.178, SC 2012.47.46, SC 2012.47.47, SC 2012.47.48 (27 specimens), WSU 5016 , WSU 5018 , WSU 5042 (30 specimens), WSU CC 506 (3 specimens), WSU CC 507 (2 specimens), WSU CC 508 , WSU CC 509.1 , WSU CC 509.2 , WSU CC 832.2 .

Description

Anterior teeth somewhat taller than wide; lateral teeth mesiodistally wider than tall. Teeth with broadly triangular crown; large, triangular main cusp. Main cusp on anterior teeth erect, flanked by two pairs of cusplets. Main cusp distally inclined on lateral teeth, flanked by three-to-four cusplets; distal side often with one more cusplet than mesial side. Cusplets large compared to overall size of main cusp; triangular, divergent, decreasing in size towards the crown foot; terminal cusplet can be difficult to distinguish from preceding cusplet. Cutting edges on main cusp nearly straight on anterior teeth, more convex on lateral teeth; all cutting edges smooth and continuous. Labial crown face flat; lingual face concave; crown enameloid is smooth. Root bilobate with short, pointed to rounded, diverging lobes. Lingual attachment surface flat, bisected by deep nutritive groove.

Remarks

The teeth of Pseudabdounia recticona gen. et comb. nov. have two-to-four pairs of lateral cusplets, distinguishing them from those of Abdounia enniskilleni and Abdounia minutissima , which have only a single pair. Teeth of Pseudabdounia claibornensis gen. et comb. nov. have four-to-eight pairs of cusplets. Although the anterior teeth of A. beaugei only have a single pair of lateral cusplets, the lateral teeth have two pairs. These lateral teeth differ from those of P. recticona gen. et comb. nov. by having lateral cusplets that are more separated from the main cusp. In contrast, the cusplets on the lateral teeth of P. recticona gen. et comb. nov. are joined to the main cusp and the teeth are more broadly triangular in outline.

Stratigraphic and geographic range in Alabama

The specimens in our sample were collected from the lower Tallahatta Formation at site ADl-1, the Tallahatta Formation at site AMo-8, the contact of the Tallahatta and Lisbon formations at sites ACh- 14, ACov-11, and ACon-6, the basal Lisbon Formation at site ACov-11, and the contact of the Lisbon Formation and Gosport Sand at site AMo-4. Upper Ypresian to middle Bartonian, zones NP14 to NP17.

Figures

Fig. 32. Pseudabdounia claibornensis (White, 1956) gen. et comb. nov. and P. recticona (Winkler, 1874) gen. et comb. nov., teeth. A–R. P. claibornensis gen. et comb. nov. A–C. MSC 37591, anterior tooth, basal Gosport Sand. A. Labial view. B. Mesial view. C. Lingual view. D–F. MSC 37563.20, lateral tooth, basal Gosport Sand. D. Labial view. E. Mesial view. F. Lingual view. G–I. MSC 37563.16, lateral tooth, basal Gosport Sand. G. Labial view. H. Mesial view. I. Lingual view. J–L. MSC 188.88, lateral tooth, basal Gosport Sand. J. Labial view. K. Mesial view. L. Lingual view. M–O. MSC 37563.28, lateral tooth, basal Gosport Sand. M. Labial view. N. Mesial view. O. Lingual view. P–R. MSC 37563.30, lateral tooth, basal Gosport Sand. P. Labial view. Q. Mesial view. R. Lingual view. — S–JJ. P. recticona gen. et comb. nov. S–U. MSC 35767.1, lateral tooth, lower Tallahatta Formation. S. Labial view. T. Mesial view. U. Lingual view. V–X. MSC 37318.3, lateral tooth, basal Lisbon Formation. V. Labial view. W. Mesial view. X. Lingual view. Y–AA. MSC 37193, lateral tooth, Tallahatta/Lisbon formation contact zone, courtesy of T. Prescott Atkinson. Y. Labial view. Z. Mesial view. AA. Lingual view. BB– DD. MSC 37167.1, lateral tooth, Tallahatta/Lisbon formation contact zone, courtesy of James Lowery. BB. Labial view. CC. Mesial view. DD. Lingual view. EE–GG. MSC 35767.2, lateral tooth, lower Tallahatta Formation. EE. Labial view. FF. Mesial view. GG. Lingual view. HH–JJ. MSC 37167.2, lateral tooth, Tallahatta/Lisbon formation contact zone, courtesy of James Lowery. HH. Labial view. II. Mesial view. JJ. Lingual view. Scale bars: A–R = 5 mm; S–JJ=2 mm.